Really good one! Going with this genre, the addictive quality is of course already almost a given. For me, presonally, the game was maybe a tad too easy, especially the piercing shot almost trivialises it a bit. And the music played in a really crunchy way with some popping - but that one is probably a problem on my end, I've had that happen with a few games here.
Those are really nitpicks, though. The art especially is great! Just a really well-done game.